Automated undeliverable subscriber rescuing has been enabled. Subscribers are automatically moved out of "undeliverable" if they are sent an email which does not bounce within the next 24 hours. The manual options remain.

The metrics on the home page are:

Subscribers: The number of unqiue email addresses in the system.

Circulation: The number of email feed pairs (so if I subscribe to two feeds, I contribute a count of two to the circulation total).